Well explosive device



Oct. 1, 1946. TE 2,408,419

WELL EXPLOSIVE DEVICE Original Filed March 17, 1939 g- 1 3 H 2 2325 i i l I I! {III/1115mm Patented Oct. 1, 1946 UNITED STATES. PATENT orncs 2,408,419 v WELL EXPLOSIVE DEVICE James Lewis Foster, Wichita Falls, Tex.

Original application March 1'7, 1939, Serial No. 262,531. Divided and this application December 2, 1942, Serial No. 467,657

9 Claims. (Cl. 89-1) This application is a division of my prior apearth formation, showing the tool partly in eleplication on Process of treating wells, Serial No. vation and partly in section, disposed in a well; 262,531, flied March 1'7, 1939, now Patent No. Fig. 2 is a fragmentary horizontal section 2,307,729, granted January 5, 1943. through the tool, on the line 2-2 of Fig. 1;

This invention relates to an apparatus for g, Fig. 3 is a longitudinal section through a form placing an explosive projectile in a subterranean of a projectile used in connection with the tool;

formation, and more particularly to the firing of Fig. 4 is a similar view of a modified form of these projectiles from a well into a fluid-bearing projectile used in the tool; and formation to increase the recovery of said fluid. Fig. 5 ha diagrammatic view of a wiring dia- By placing a small amount of the explosive at gram for sequentially firing a plurality of exvarious points in the earth formation and detoplosive charges within the tool. I nating this explosive, more advantageous results With more particular reference to the drawing,

maybe obtained than by placing a large amount the numeral i represents the body of a tool which "of explosive within the bore hole and detonating carries a plurality of radially disposed explosive it there. v chambers or cannons 2 which are preferably Heretofore, it has been common practice to spaced along the length of the tool, preferably lower large charges of high explosives into a well being turned in diilerent radial directions relative and to detonate these charges by -mechanical or thereto. These cannons have removable barrels time-clock means. These charges, which con- 3 which may be taken out of the tool I, being sist of from ten quarts to five hundred quarts of removably placed in sockets 4 in the tool i. The pure nitroglycerin, .are dangerous to the workremovable barrels 3 are held in place in recess 1 men handling them, dangerous to the public safeby bolts 6 and within the outer end of this barrel ty, since they must be moved over the public is disposed the threaded bushing 8 which engages highways, and'often do extensive damage to the shear ring H and causes the ring to seat upon well casing and equipment. The reason that gasket 5. This prevents moisture from entering these charges must be so large is that they dethe powder chamber 9. This threaded bushing pend entirely on concussion and reverberation to forms an extension of cannon barrel 3 and is reachieve the desired result of loosening and removed each time a new projectile is inserted.

moving that part of the formation immediately Before inserting the tool into a well, an exadjacent the bore hole, wherein they are applosive charge 9 is placed in each of the cannon proximately axially disposed at the time of the bores or chambers 2 behind an explosive projecdetonation. tile ID or Iii therein, upon which projectile an While the drawing shows one form of apparaexpansive shear ring II has been fitted and tus for practicing the invention, it is to be'underslipped into an annular recess i2 in the cannon stood that the invention relates to provisions for bore 2.

the more advantageous placing of explosives con- A percussion cap I3 is fitted into an opening tained in projectiles at a point in the earths M in the cannon barrel 3, longitudinally of the stratum removed from the bore hole, so that the tool, so that firing in l5 will detonate the cap portion of the stratum lying between the point i! and theadjacent explosive charge 9 upon the of explosion and the bore hole will be driven to- 40 striking of the firing pin i5 by the hammer ward the bore hole by the force of the explosion. ii. The hammer I6 is operated by an electro- It is obvious that varied results such as blastmagnetic coil or solenoid i1 when electrical ening down a portion of the wall of t e well, driving ergy is supplied thereto. The entire solenoid gathering holes with basins at the outer ends mechanism is contained in a casing i8 and may thereof, providing entries for formation solvents, be inserted into or removed from the tool through providing enlarged sections in the bore hole for the recess 4 therein. the anchoring of cement bridges, and other simi- A single wire, with grounded return circuit, iar functio may be produced by varying the is shown and a relay switch is connected within forces of the explosives involved in the invention this wired circuit 2| and has connection with the and by varying the types of projectiles used. solenoid which is next to be operated so that the These variations are to be considered within the projectiles may be sequentially fired from cannon scope of the invention herein disclosed. bores 2 by closing and opening a switch iii in The accompanying drawing shows a preferred said circuit (Fig. 5) ,which switch is located at embodiment of the invention, in which: thesurface or at the mouth of the well. Upon Fig. 1 is a fragmentary vertical section of an closing the switch IS, a source of electrical, en-

ergy, such as a battery 20 is conn'ectedwith circuit 2| leading to the solenoids H, which are in parallel with the circuit through secondary switches.

A switch arm 22 rests on contact plate 23 (Fig. 2) which closes the circuit to the coil l1 and actuates the hammer i6 by the force exerted in magnetic coil l1. As the hammer I6 is moved to strike firing pin l (Fig. 1), a pointed end 24 of the hammer, which pointed end 24 is made of fiber or other insulating material and which normally holds the switch arm 22 retracted, is withdrawn and permits switch arm 22 to be moved into the position shown in dotted lines and indicated at 22' (Fig. 2), by a spring 45 acting on the arm 22 until said switch'arm is stopped by a stop pin 48.

In this position the contact point 25 is still in contact with plate 23, although having moved to the opposite side of the axis of the hammer l6; however on the breaking of the circuit by the manual release of the switch IS, the solenoid I1 is deenergized, releasing the hammer l6, and upon the return of the hammer l6 under pressure of spring 26 hearing thereagainst, the pointed end 24 will push the switch point oil contact plate 23 against contact 23', to dotted line position as indicated at 22'. (Fig. 2). By this movement of the switch arm 22, the first solenoid is entirely disconnected from the circuit and remains deenerglzed until the tool is removed and the mechanism reset when a new charge is inserted. A plugged opening 21 is provided through the wall of the tool I for the instrument against switch arm the same, as shown in Fig. 2.

When the switch arm 22 moves to the dotted line position 22" and engages contact 23' after firing the first charge, this closes the circuit 2| to the next succeeding solenoid I! which is then ready to be fired by again closing switch l9, as described. This operation is repeated until all of the charges have been fired.

A wire 2i is shown schematically in Fig. 1 for 22 for resetting spective solenoids, designated a, b, and c in Fig. 5. This wire is shown leading onward from solenoid c, as any number of discharge units may be used. When the tool is cross-drilled, the holes will be plugged in the usual manner.

insertion of an Several types of penetration are desirable, particularly for oil wells, two of which are shown. One type is indicated at A, where an explosive Another form of shot which may be placed,

is that indicated by dotted outline at B. The

amount of explosive 9 in chamber 2 is increased so as to drive the projectile a greater distance into the stratum than shown at A. This projectile may be so constructed as shown in Fig. 4,

that it will be blown into bits, each of the fragments cutting. a channel in the stratum, and in this manner a passage is formed for some distance out into the stratum with a basin at the outer end, and passages radiating from said basin, thus opening up producing stratum, or permitting chemicals to be introduced into certain types of formations where they will work with greater rapidity and efi'ectiveness than if introduced into the immediate bore hole of the well.

Two types of projectiles are shown in Figs. 3 and 4, type shown in Fig. 3

This

retains the projectile within the cannon barrel until the greater part of the explosive charge is burned. In this manner the full efl'ectiveness of the charge is obtained upon the shearing of expansive shear ring II.

The form of and longitudinal disposed within the chamber signed to carry the explosive charge.

The tool may be lowered into the well by any suitable means such as pipe 42 or a cable. If used on a drill stem, it can be screwed together cannon barrel, as indicated at may be removed from the well On reloading the device, a new gasket 5 and a new shear ring II, as will be required,

well as a new projectile, as the projectile will shear these each time the cannon is detonated.

ID will force a portion of the.

The lower end of the tool is preferably tapered to a point to facilitate its insertion into, as well as its removal from the well after the explosion of the projectiles when the explosives would have forced a quantity of the formation into the bore hole. 7

Iclaim:

1. In a well having a bore hole projecting into a surrornding fluid-bearing earth formation, the combination of a well casing projecting said bore to a point spaced above the lower end of the bore, an explosive device suspended within the bore, an explosive projectile carried by said device, and means on the explosive device for discharging the explosive projectile into said surrounding fiuid-bearing earth formation at a point below the casing to increase the exposed area of the fluid-bearing formation.

2. In a well having a bore hole projecting into a surrounding fluid-bearing earth formation, the combination of a well casing projecting said bore to a point spaced above the lower end of the bore, an explosive device suspended within the bore, an explosive projectile carried by said device, means on the explosive device for discharging the explosive projectile into said surroundin fluid-bearing earth formation at a point below the casing, and means for subsequently exploding said projectile in said formation to increase the exposed area of the fluid-bearing formation.

3. In a well explosive device, a cannon barrel, an explosive projectile within the barrel having an annular groove around the outer periphery thereof, an expansive ring fitted into said annular groove and secured to said cannon barrel tending to hold the projectile therein, and delay action detonating means on said projectile whereby the projectile'is adapted to penetrate the wall of a well before exploding.

4. In a well, the combination of a bore hole having a surrounding fluid-bearing earth formation, a device suspended within the bore hole, an explosive projectile carried by said device, means on said device for firing said explosive projectile into said surrounding earth formation, and means on the projectile for exploding said projectile in said formation.

5. In a well, the combination of a bore hole having a surrounding oil-bearing earth formation, a device suspended within the bore hole, an explosive projectile carried by said device, means on said device for firing said explosive projectile from within the bore hole laterally at an angle to the axis thereof into said oil-bearing formation, and means on the projectile for exploding said projectile in said formation.

6. In a well, the combination of a bore hole having a surrounding fluid-bearing earth formation, a wel1 casing projecting into the bore hole to a point above the bottom thereof, a device suspended within the bore hole, an explosive projectile carried by said device, means on said device for firing said explosive projectile into said surrounding earth formation at a point below the casing, and means on the projectile for exploding said projectile in said formation.

'1. In a well explosivedevice, a body adapted to be lowered into a well having a surrounding fluid-bearing earth formation, an explosive projectile carried by said body adapted to be projected into a wall of the well, and delay action detonating means on said projectile whereby the projectile is adapted to penetrate the wall of the well before exploding.

8. In a well explosive device, a body adapted to be suspended within a bore hole having a surrounding fiuid-bearing earth formation, said body having a barrel therein, an explosive projectile mounted in the barrel, explosive means in the barrel behind the projectile for discharging said projectile into the wall of the well, and delay action detonating means on the projectile whereby the projectile is adapted to penetrate the wall of the well before exploding.

9. In a well explosive device, a body adapted to be lowered into a well having a surrounding fluid-bearing earth formation, the body having a chamber therein, an explosive projectile carried by the body in the chamber, means for ejecting the projectile from the body into a wall of the well, and delay-action detonating means on said projectile whereby the projectile penetrates the wall of the well before exploding and causes a portion of the earth formation of the wall of the well to be directed into the chamber of the body.

JAMES LEWIS FOSTER. 

